The correct answer is D. The therapist will be able to suggest appropriate treatment.
Step-by-step explanation:
The Diagnostic and Statistical Manual of Mental Disorders (DSM) is a document that helps health care professionals to diagnose and treat different mental disorders. Indeed, this document acts as a guide by defining several mental disorders, its symptoms and possible alternatives for treatment. The last edition of this document is the fifth edition of DSM-5 published in 2013.
According to this, the fact autism spectrum disorder is included in the DSM-5 makes Marshall's therapist more likely to suggest appropriate treatment because, the DSM-5 suggests therapies or treatments for disorders included in it, while disorders that are not included in this document might be difficult to diagnose or treat due to lack of parameters or information about them.